Yarn and fabric product and process



March 24, 1964 M. BAEBLER YARN AND FABRIC PRODUCT AND PRocEss Original Filed Nov. '7, 1956 INVENTOR. /VA RMA /v 5A EBA Ef? ZM, M ,1w/d

United States Patent O 3,125,848 YARN AND FABRIC PRODUCT AND PRUCESS Marijan Baebler, Wattwil, Switzerland, assigner to` Heberlein Patent Corporation, New York, NX., a corporation of New York Continuation f applications Ser. Nos. 620,957 and 620,958, Nov. 7, 1956. This application Dec. 27, 1962, Ser. No. 248,841

24 Claims. (Ci. 57140) This invention relates to a process for making an improved stretch nylon or similar organic synthetic fiber yarn, and to the yarn product. It also relates to articles, including hosiery, made from the improved stretch yarn and to a process for making such articles. This application is a continuation of both of my earlier copending United States patent applications Serial Numbers 620,957 and 620,958 both filed November 7, 1956, and both now abandoned.

In Billion U.S. Patent 2,564,245 a process is described for producing superpolyamidic yarn having permanent crimping and fluiing properties. The superpolyamidic yarn is highly twisted, set and backtwisted, during which process it shrinks. The yarn is plied with another yarn treated in the same manner but twisted in an opposite way. The yarns so plied, having respectively an S-twist and a Z-twist, thus compensate one another, so that the resultant yarn has practically no directional torque. This is the conventional process which has been widely practiced commercially. Socks and stockings made of stretch nylon prepared in accordance with the Billion patent are Well known. Such hosiery is ordinarily made of plied stretch yarn as aforesaid, or it may also be fabricated of S and Z yarns knitted or woven to give a compensated effect.

Where S and Z yarns are plied, each yarn must be individually processed under about the same conditions except for the direction of twist, in order to produce a compensated yarn. In addition, with such composite yarn it must be made of at least two yarns, each having one-half of the denier desired in the linished yarn.

An object of the present invention is to provide a process for producing a single end yarn which does not require the plying together for compensation of two yarns, each with an opposite directional torque; and to produce thereby a product ready for knitting or other use.

Another object of the present invention is to provide a woven or knitted article such as a sock or stocking made of yarn which does not require such compensation of torque therein.

In carrying out my process for producing yarn I ernploy a yarn of symthetic organic liber, by which expression I intend to define polyamidic fibers, such as those made from polyhexamethylene adipamide or from epsiloncaprolactam, polyacrylonitrilic iibers and polyester ibers. The yarn employed usually comes on the market with relative few turns per meter, namely about 0 to 80 turns per meter. Such yarn, in highly twisted state, is originally set in the lirst step by heating in accordance with my invention. By highly twisted in this first step I mean a yarn that is twisted at a twist of the order of about 1000 to 6000 turns per meter. This yarn is set originally at a temperature of the order of 100 to 225 C. I prefer to carry out this twisting and setting by the so-called falsetwisting process, which is a well known process by which the yarn is continuously passed through a heating zone and is set therein while being continuously highly twisted to the extent indicated, and detwisted. The temperature and high-twist ranges above are used where false-twisting is employed. Instead of the false twisting mentioned, the conventional steps referred to above may be employed ice in this original setting and detwisting. In the second step the yarn so set and detwisted by the false-twist or conventional process is then retwisted to no higher number of twists than in the lirst step, in the opposite direction, and is reset in this condition. The retwisting and resetting again are preferably done in a false twisting machine. The number of twists placed in yarn in both false twist and conventional methods may be equal or different in the second step from the number of twists in the rst step. The resetting temperature range for false twists is -225 C. For the conventional method, the resetting is done with saturated steam at 0-5 atm. gauge pressure. Either or both steps 1 and 2 may be made accordingly by the false twist or conventional method.

In carrying out my process, the retwisting is thus done at the same or a lower number of twists and the resetting at the same or a lower temperature than in the original or rst setting step. After retwisting and resetting detwisting occurs. In the false twisting method the detwisting is substantially to the number of twists of the gray yarn. In the conventional process the detwisting may be to zero or several twists in the S or Z direction with respect to Zero.

Yarn so produced is permanently crimped and has good inherent elasticity. It is a single end multi-filament yarn. The yarn has a torque or twist which develops on wetting as described below. Thus the yarn resulting from the two steps of my process may show no actual torque, but on wetting a torque will develop. This torque will be in the direction, either S or Z, of the twist given the yarn in the rst step. On the other hand, yarn produced from the two steps of my process may show an actual torque and this actual torque will be in the direction of the twist given the yarn by the second step of my process, namely, in either Z or S direction. In such case, when this yarn is wetted as described below, it will develop a torque due to and in the direction of the twist in the irst step. If this torque or twist of the first step so developed by wetting equals the actual torque of the second step, then the yarn will become a yarn without substantial torque. If the torque developed on wetting is greater than the actual torque of the second step, then the nal yarn on wetting will have a torque in the direction of the rst step. If it is less than the torque of the second step, then the resultant yarn will have the torque of the second step.

My novel fabric product includes a woven or knitted article containing a permanent elastic crimp single-end yarn of organic synthetic fibers as above described. The yarn has a torque S or Z, which develops on wetting the yarn, as noted above. Ordinarily, it also has an actual torque which is substantially equal to and in the opposite direction to the torque which develops on wetting, that is the wet torque.

The wetting treatment referred to above defines treatments to which yarns are normally subjected in scouring, dyeing or boarding knit or woven fabrics. An important characteristic of my improved yarn is that on knitting a fabric produced from a yarn having an actual torque, the resulting fabric will have wales inclined to the vertical in the opposite direction to that of the torque. For example, a yarn with an S torque will produce a fabric with wales inclined in a Z direction and vice versa. On wetting such fabric, the wales will change to a substantially vertical position if the torque developed on wetting is equal to the actual torque of the yarn. If it is unequal, the wales will incline either in the same direction as the wet torque or in the opposite direction to the wet torque, depending on whether the torque is greater or less than the actual torque.

In accordance with one aspect of the present invention I may knit a yarn in which the Wet torque has been deaisselle veloped by scouring or dyeing, for example, into an article after this finishing treatment, and if its actual and wet torques are equal such knitting will produce a fabric with vertical wales.

In the accompanying drawinqs forming part of this application:

FIG. 1 shows a doubled length of stretch nylon yarn freely suspended, made in accordance with my invention for making yarn.

FIG. 2 is a microscopic, highly enlarged portion of the yarn shown in FIG. 1, said portion being designated by a bracket in FIG. 1, and marked FIG 2. Y

FIG. 3 is a portion of a knitted fabric which has an angular distortion in the S direction.

FIG 4 is a highly enlarged and schematic view of the fabric shown in FIG. 3.

FIG. 5 is the fabric of FIG. 3 after wetting same, showing the wales in vertical position.

FIG. 6 is a highly enlarged and schematic View of the fabric shown in FIG. 5, with the wales in vertical position.

For simplicity the yarns in FIGS. 3-6 are shown in smooth form. They would actually apear somewhat fuzzy as in FIG. l.

Referring now to the figures, the numeral 1 designates a strand of the nylon yarn which has been doubled and then freely suspended. The yarn has an actual unidirectional torque and accordingly tends to turn about the vertical axis, forming a series of wide loops marked 2. The amount of torque is small, as shown by the relatively few large loops formed.

In FIG. 2 the microscopic enlargement of` the portion of the strand l shows that this strand is made up of filaments which are crimped and irregularly intertwined with one another in a form characteristic of stretch nylon yarn.

The strand 1, as stated, has an actual unidirectional torque or tendency to twist about its vertical axis when held in the form of a doubled loop. Thisyarn has a wet torque, that is, atorque which is developed by wetting same as described above. lf this yarn has a wetting torque equal to the actual torque, the resulting yarn on wetting will be a yarn without torque. On the other hand, as stated above, if the wet torque is greater than the actual torque then the yarn will have a torque in the direction of the wet torque. If it is less than the actual torque then the yarn on wetting will have a torque in the direction of the actual torque.

Referring to FIG. 3, the knitted fabric there shown has wales inclined to the vertical in the S direction. When the yarn shown in FIG. 1 is knit into fabric as shown in FIG. 3, this inclination occurs because of the unidirectional actual torque o the yarn. In the highly enlarged showing in FIG. 4 the wales 3 are shown as extending from left to right at a small angle with respect to the vertical axis of the fabric. The yarn also has a wet torque which is substantially equal to the actual torque. On wetting the fabric, as above stated, the wet torque appears and the wales become vertical. Wetting may be done by simple immersion of the fabric in water or by ordinary finishing processes as above stated at ltimes and temperatures depending on the conditions of treatment of the yarn, and the character of the yarn, in accordance with my invention. l

Thus in FIG. 5 is shown the fabric of FIG. 3 after such wetting treatment. It will be noted that the wales 3 are substantially vertical. In other words, the inclination shown in FIGS. 3 and 4 has been corrected so that the wales are in the vertical position as shown in FIGS. 5 and 6.

In using nylon yarn, if the conditions of temperature and twist for the first and second steps are not carefully observed, the wales may not appear in exactly vertical position on wetting. In other words, they may have an angle oit inclination to the vertical. For some fabrics this is not objectionable, but for the majority of fabrics,

Llincluding socks and stockings, it is important that the wales be vertical.

Instead of knitting the sock or other fabric and then correcting the angular distortion by wetting, the yarn itself employed in the fabric may be wet to produce a yarn without substantial torque,` and such yarn may then be employed for knitting purposes to give a fabric with substantially vertical wales.

The following are examples of the manner in which I now prefer to practice my invention. Itis to be understood that the examples are illustrative, and the invention is not intended to be limited thereto, except as indicated in the appended claims.

EXAMPLE 1 First step: A polyamide yarn, made ofthe polycondensation-product of hexamethylenediamine and adipic acid, 7 den., 23 filaments with a twist of 30 t./m. Z is hightwisted on a ring-twisting machine to approximately 3000 t./m. Z, set during 20 'minutes with saturated steam at 2 atm. gauge pressure and then detwisted beyond the zero point to approximately 200 t./m. S. Second step: Then the yarn is temporarily hightwisted on a falsetwisting machine toapproximately 2000 t./m. S and in this highly twisted state steamed` at 1.5 atm. gauge pressure for approximately 1.5 seconds. One obtainstherewith a permanent intensely and evenly crimped inherently'elastic single yarn. The yarn so produced has a crimp retentivity of 73% and a maximum elongation of 210%.

- EXAMPLE 2 First step: A polyamide yarn, lmade of the polycondensation-product of hexame'thylene diamine and adipic acid (nylon) 30 den., 10 filaments with atwist of 30 t`./m. Z is temporarily hightwisted by means of a'falsetwisting machine l'to approximately 4500t./m. S and in this hightwisted state Set with saturated steam at 4.5 atm. gauge pressure for 2 seconds. Then, in a second step, the yarn is hightwisted with a falsetwisting machine to approximately 4500 t./m. Z, whereby it isset with saturated steam inthe hightwisted state at l atm. vgauge pressure for 2 seconds. One obtains'by this procedure a permanent single inherently elastic crimped yarn,with a pleasant hand. The yarn so producedV has a crimp retentivity of 87% and a maximum elongation of 150%.

ythe zero point to approximately 56 tJm. S. Second step:

Then, the yarn is'hightwisted on a falset'wistingmachine to approximately 3000 t./m. S and fixed in this hightwisted state with hot air of'180f C. during 1.5 seconds.

LOne obtains therewith, an inherently elastic single,` crimped yarn. The yarn so produced'has a crimp retentivity of 76% and a maximumelougation of 190%.

EXAMPLE 4 First step: A nylon `yarn V30 den., 10 filaments with a twist of 280 t./m. Z is temporarily hightwisted by means of a falsetwisting machine to approximately Yi500 t./m. S and set in the hightwisted state with hotv air of 225 C. during 1.9 seconds. Then in the second step, the yarn is hightwisted on a falsetwisting machine to approximately 3000 t./m. Z,whereby it is heated in the hightwisted state with hot air of -180 C. during approximately 1.6 seconds. The single crimped yarn produced is inherently highly elastic. The yarn so produced has a crimp retentivity of 89% andia maximum elongation of 110%.

EXAMPLE 5 e First step: A polyamide yarn, as per Example 1, is hightwisted on a ringtwisting machine to `approximately 3000 t./m. Z, set with saturated steam at 2 atm. pressure during 20 minutes and detwisted beyond the zero point to approximately 230 t./m. S. Second step: Then the yarn is hightwisted on a ringtwisting machine to approximately 2000 t./m. S and and set with saturated steam at 0.3 atm. gauge pressure lduring 5 minutes, and then detwisted beyond the zero point to approximately 1110l t./rn. Z. One obtains inherently, highly elastic, crimped yarn with a pleasant hand. The yarn so produced has a crimp -retentivity of 70% and a maximum elongation of 210%.

EXAMPLE 6 First step: A nylon yarn 30 den., 10 tlaments, with a twist of 310 t./m. Z is temporarily hightwisted by means of a falsetwisting machine to approximately 4500 t./m. S and set in the hightwisted state Iat a temperature of 200 EXAMPLE l1 First step: A polyester yarn of polyethyleneglycolterephthalate 100 den., 48 iilaments, with a twist `of 30 t./m. S is hightwisted on a ringtwisting machine to approximately 2400 t./m. S and set in the hightwisted state C. `during 3 seconds by means of an electrical heating unit, 15 With Saturated Steam of 3 atmgauge Pressure during 20 as described in the United States patent `application Serial mnutes- Then the yarn is detWlSted on the rngtWlstlng No. 601,202, now U.S. Patent No. 2,823,292. Then in machine beyond the zero point to about 120 t./m. Z. the second step the yarn `is hightwisted on la `falset-wisting Second steP Thereupon the So treated yarn is temPorarlly machine to approximately 3500 t./m. Z, whereby it is hightwisted by means of a felsetWlStlng machine to aP' heated in the hightwisted State with hot air of 160 C, proximately 1600 t./rn. Z and set in the hightwisted state during 2.2 seconds. The yarn so produced has a crimp With hot 'air of 140 C- during |1 second- There is 0b- -retentivity of 89% and a maximum elongation of 160%. `tained a highly elastic crimped yarn Wflth e tWlst of 12'0 EXAMPLE 7 t./ Z having a crimp retentivity of 82%.

The following is a tabulation of additional tests car- First step: A nylon yarn 30 den., 10 filaments, with a 25 ried out on nylon yarn:

` Hot Air Hot Arr Apps'mle y Crimp Maximum Denier Temp., Twrstl Temp., Twist;2 Reten- Elonga- 0.2 0.2 tivity, tion,

Stepl Step2 Percent Percent Example 12 15/3 220 4,724.40t./m. z 161 2.5 1.5 2,952.75 um. s 94 213 Example 1a 0,10 220 4,429.13 mm. Z 170 2 1.5 2,952.75t./m. s se 131 Example 14 70/34 220 3,11o.23t./m. Z 170 1.5 1.2 2,362.20 t./m. s 70 10o Example 15 14o/6s 220 2,362.20 t./m. S 172 1.5 1.1 1,748.03 t./m. Z 70 63 l First step. 2 Second step. twist of t./m. Z cis temporarily hightwisted and set in In each of Examples 1 to 15, the tension of the yarn the hightwisted state under conditions as described in Ex- Will vary between 0 15 grams depending on the denier; ample 6. Then in a second step the yarn is hightwisted in the lower the denier, the less tension is required. a falsetwisting machine to about 500` t./m. Z and heated Yarns made by Examples l to 15 upon completion of in the hightwisted state at a temperature of 170 C. durstep 1 are shrunk yarns, =i.e., yarns Without `residual shrinking 1.9 `seconds by means of an electrical heating unit. age. Step 2 is conducted on such shrunk yarn and, so The yarn so produced has Ia crimp retentivity of 95% far as I `am aware, -no such twisting, setting and detwistand a maximum elongation of 150%. 43 ing of shrunk yarn has heretofore been proposed.

In order to measure crimp retentivity and maximum EXAMPLE s elongation of a yarn treated according to my process, the First step: A nylon yarn, 20 den., 7 filaments, with a yarn must 'Primarily 'be allowed to crimp Completelytwist of 16 t./m. Z is temporarily hightwisted on a false- This S Performed by eXPoslng the yam ln the form of a twisting machine to approximately 50100 t/m. Z .and set small skein for about 5 minutes to the action of moist tin the hightwisted state during 3.1 seconds at a tem-pera- Steam thereby allowing the yern to contract 'freely- SZed ture of 225 C. by means of an electrical heating unit, or -Oiled yarn should be Washed yfree of extraneous subes described du the aforementioned United States patent stances before Steaming- The crimped yarn is then cnnapplication Serial No. 601,202 1. Then in a second step dltioned at 20 centlgrade 'and 65 Percent relatlVe lluthe yarn is falsetwisted to about 4000 lt./m. S and heated mldtyin the hightwisted state with het lair ef 170 C. during 2.5 To determine Crimp retentvity, a length of 30 centseconds. The yarn so produced has a crimp retentivity meters of the completely crimped yarn 'is suspended `on of 88% and a maximum elongation of 1180% one end and `after preloading for 2 minutes with 0.002 g. per denier the exact length (a) of the preloaded yarn 4is EXAMPLE 9 60 measured. The yarn is then immersed for 30 seconds in First Step; A nylon yamy 270 den 7 filaments with a water of 60 ntigrade containing 2 g. of wetting agent .twist er 16 t/m. z is faisefwisted Aand Set in the high- 0f the type 0f Nekal BX (General Dyestuff Corn); twisted state under conditions las described in Example 8. thereafter the Wet yarn is suspended for tWO mnuteS With Then in a second step the yarn is falsetwisted to about a 'load 0f 0-03 g- Per denier and the length (b) of the 3500 t./m. S and heated in the hightwisted state with hot stretched yam measured A fter taking 'olf the load, the air of 180 C `during 2.2 Seconds The yam so, produced yarn 1s drled wrtl'rout any tension at 50 to 60 centigrade. has a crimp retentivty of 90% and a maximum e10nga After being conditioned for one hour Iat 20 centigrade tion of 209%- and 65 percent relative humidity, the yarn is loaded for EXAMPLE 10 two minutes with 0.002 g. per denier and its length (c) I measured. The crimp retentivity in percent is then cal- Flrst steP A Polyester yarn ot Polyethyleneglycolterculated according to the following formula: ephthalate 40 den., 24 nlaments, -w1th a twist of 30 t./m. S is twisted on a ringtwisting machine to approximately b 0.100 t./m. S. Then the yarn -is temporarily hightwisted by b a 1N0W patent No. 2,823,292. 75 To determine maximum elongation a length of about 30 centimeters of the completely crimped yarn is suspended on one end and preloaded with 0.002 g. per denier for 2 minutes, whereupon the Aexact length (x) otthe preloaded yarn is measured; The yarn is -now loaded rwith 0.8 g. per denier for -two-minutes and then the llength l(y) of the so stretched-yarn is measured. The maximum elongation in percent is calculated according to the formula below:

The yarn of each of the above examples is then formed into va stocking as for instancein the manner described in Example 16 below. The stocking is then scoured in a relaxed condition at 60-70" C. for 30 minutes in a bath containing 2 grams gepal CO-630 (or equivalent nonionic washing agent) and 0.5 gr. soda ash per liter of water, rinsed for 3 minutes with warm (about 50 C.) water and then 5 minutes in cold tap water, then carefully centrifuged and dried in a relaxed condition at about Prior to the scouring operation mentioned the knitted material will show wales inclined to the vertical. The direction of the inclination will be in the direction opposite to that of the second high twisting operation. Upon scouring the knitted material as above, however, this inclination is substantially eliminated and the knitted material thereafter shows Verticalwales. The scouring thus not only cleans the goods, but also removes the inclination, asindicated above. -Y Y' The following are further specific examples of the manufacture of hosiery in accordance with. my invention. Yarn in accordance with my invention is prepared, then carried through ,specic processes of.. hosieryknitting, both circular and full-fashioned knitting, followed by speciiic dyeing and other finishing steps.

EXAMPLE 16.-srocKrNo FROM is-DnNiER YARN The yarn was prepared in accordance with the procedure in Example 12 above.

Knit on Scott -& Williams circular knitting machine 400 needles, 3% cylinder under drag tension,that is, the tension exerted on the yarn by the knitting machine but without any. tensionL applied such as by a spring or disc tension. Theneedles are 75 gauge and the latchesSO gauge. Heel and toe and welt are made of normal yarn inthe usual manner. Knit under normal conditions.

The stocking has wales inclined to the vertical.

Dyeing and vFinishing (l) The stocking is scoured in a bath containing a mild soap for -30 minutes at a temperature not to exceed 65 C.

(2) The stocking is then dyed with dispersion dyestufts for 20-30 minutes in a bath whose temperature is about 65 C.

(3) The boarding is carried out on a small form for 2 minutes at a steam temperature of 116 C.

The above steps of dyeingy and nshing areV the same as used for other stretch stockings, that is, they constitute standard practice. The stocking so produced shows wales are substantially vertical. It has substantially no shine. It has a good hand, that is, it is softer than stockings knit from untreated nylon. It has a better tit than such stockings due to its stretch character.

EXAMPLE l7. SOCK FROM vl40-DENIER POLY- AMDE YARN The yarn employed herein was prepared in accordance with Example l5 above. The yarn was knit on a Scott & V-Jilliamscircular knitting machine as above in Example 16 with respective needle spacing. The socks so a dull effect. Its

knitted were put ina bag .and washed in water at a temperature of 50.to 65 C. for 15420 minutes. The socks then showed vertical wales. They were then preboarded at 116 C. for 11/2 minutes at di'yheat. They were then dyed at about 65 C. using neutraldyeing acid dyestuis. They were then finished in thev usual manner.

The socks showed a dull mat appearance. They are better tting, due to their stretch character, than socks knit from ordinary 140-dcnier nylon. They have a good soft hand.

The dyeing in each oi' Examples 16 and 1:7 was made with dyestuis selected `fromthe following: DuPont acetarnine yellow N; DuPont acetamine yellow CG (Pr 242); DuPont acetamine scarlet N; and DuPont acetamine blue FS. The temperature of the dye baths may range from 60 C.-70 C.

EXAMPLE 18.-STGCKING MADE FROM iO-DENIER POLYESTER YARN YKnitting The yarn employedherein was prepared in accordance with. Example 1 0 above. The. yarn was knit. on a Scott & Williams circular knitting machine 300 needles, 31/2 cylinder under slight tension.

Dyeing und Finis/zing vwas performed in a bath'containing per liter l gram of the sodium usalt of the oleyl-alcohol-sulphate and the following dyestuiis:

. Percent Celanthrene Fast Yellow conc. 300% (Pr 534) 1 0.03 yAcetamine Orange GR conc. 17.5% (Pr 43)--" 0.04 Celanthrene Brill. Blue FR conc. (Pr 228)---- 0.01

1Percents based on the dry Weight of the goods to be dyed.

The stocking was entered into the dyebath at 50 C., whereupon the` temperature of the liquor was slowly raised to the boil.and maintained at that temperature for one hour. Finally the'stocking was boarded on a small form at a steam temperature of C.

The stocking so produced vshows a reduced lustre, a soft silky hand and has a good t due to stretch character.`

I claim:

l. A-method of making a continuous lament stretch yarnof the synthetic `resinous type which comprisessubiecting the yarn to a rst false twist in one direction and heatsetting the yarn and subsequently subjecting the so twisted and heat-set yarn to a false twist in` the opposite direction andY heat treating in the second stage of false twist at a temperature lower than in the iirst stage.

2. A method as setforth in claim l wherein the false twist in the second stage is to alower number of twists than the rst false twist.

3. A method` as set forth in claim 1 wherein the false twist in the second stage is to substantially thesame number of twists -as the tirs-t `false twist..

4. A method, of making a stable stretch multiiilament yarn of the synthetic resinous type which comprises subjecting the yarnr to a tirst false twist of at least 30 twists per linear inch in one Adirection and heat setting the yarn and subsequently subjecting the so twisted and heat-set yarn to substantiallyy the sameW degree of false twist but in the opposite direction and heat-treating the yarn in .the second stage of false twist at a temperature lower than in the iirst stage.

5. AV method of make a continuous filament stretch Y yarn of the. synthetic resinous type which comprises subjecting the yarn to a iirst false twist in onedirection and heat setting the yarn and subsequently subjecting the so twisted and heat-set yarn to a false twist in the opposite 9 direction and heat treating in the second stage of false twist at a temperature substantially the same as in the rst stage.

6. A method of making a continuous filament stretch yarn of the synthetic resinous type which comprises subjecting the yarn in a first stage to a false twist in one direction and heat-setting the yarn whereby a torque is imparted to the so treated yarn in a direction opposite to the direction of twist and subsequently subjecting the so twisted and heat-set yarn in a second stage to a false twist in the direction opposite to that of the first stage false twist, and heat-treating the entire yarn in the second stage of false twist, the false twist and temperature to which the yarn is heated in the second stage being no greater than in the fhst stage.

7. A method of making a continuous filament stretch yarn of the synthetic resinous type which comprises subjecting the yarn to a first false twist of the order of about 1000 to 6000 turns per meter and heat setting the yarn and subsequently subjecting the so twisted and heat-set yarn to a false twist in the opposite direction and heat treating the entire yarn in the second stage of false twist at a temperature of the order of about 100 to 225 C., but no higher than in the first stage false twist.

8. A process as set forth in claim 7 wherein heat treating in the second stage of false twist is at a temperature lower than in the first stage.

9. A process as set forth in claim 7 wherein heat setting of the yarn in the first stage of false twist is at a temperature of the order of about 160 to 225 C.

10. A process as set forth in claim 7 wherein the false twist in the opposite direction is of the order of about 400 to 6000 turns per meter.

11. A continuous method for producing a continuous filament stretch yarn of the synthetic resinous type which comprises continuously subjecting a raw continuous filament synthetic resinous yarn in a first stage to a false twist in one direction and heat-setting the yarn whereby a torque is imparted to the so treated yarn in a direction opposite to the direction of twist, and immediately thereafter continuously subjecting the so twisted and heat-set yarn in a second stage to a false twist in the direction opposite to that of the first stage false twist, and heattreating the entire yarn in the second stage of false twist, the false twist and the temperature to which the yarn is heated in the second stage being no greater than in the first stage.

12. A false twisted substantially uniform permanently crimped continuous filament stretchable single-end yarn of the synthetic resinous type having an actual unidirectional torque and a latent torque which develops on wetting and is in the opposite direction to said actual torque.

13. A multiiilament nylon yarn as set forth in claim 12.

14. A false twisted permanently crimped continuous 10 iiiament stretchable single-end yarn of the synthetic resinous type having an actual unidirectional torque and an opposite latent torque which develops on wetting and is less than the actual torque ofthe yarn.

15. A false twisted permanently crimped continuous filament stretchable single-end yarn of the synthetic resinous type having an actual unidirectional torque and an opposite latent torque which develops on wetting and is greater than the actual torque of the yarn.

16. A false twisted permanently crimped continuous filament stretchable single-end yarn of the synthetic resinous type having an actual unidirectional torque and an opposite latent torque which develops on wetting and is substantially equal to the actual torque of the yarn.

17. A permanently crimped continuous multifilament stretchable single-end yarn of the synthetic resinous type false twisted and heat set over its entire length which exhibits substantially no torque following wetting.

18. A permanently crimped continuous filament stretchable single-end yarn of the synthetic resinous type false twisted and heat set over its entire length which exhibits substantially no torque prior to wetting but exhibits torque following wetting.

19. A fabric fashioned of a permanently crimped, highly stretchahle, single-end, multitilament synthetic organic yarn, which fabric exhibits a tendency to curl prior to wetting but substantially no tendency to curl following wetting.

20. A fabric fashioned of a single-end of permanently crimped, highly stretchable, multifilament synthetic organic yarn, which yarn exhibits torque prior to wetting but substantially no torque following wetting.

21. A fabric fashioned of permanently crimped, highly stretchable, single-end multiiiiament synthetic organic yarn, the filaments of which are irregularly intertwined, all of which yarn exhibits a unidirectional torque prior to wetting and substantially no torque following wetting.

22. A knit fabric fashioned of a single-end of permanently crimped, highly stretchable, multilament synthetic organic yarn, which yarn exhibits torque prior to wetting but substantially no torque following wetting.

23. A knit fabric having a tendency to curl following wetting as evidenced by inclination of the wales thereof from the vertical fashioned of the single-end yarn of claim 15.

24. A method as set forth in claim 1 wherein the continuous filament stretch yarn is a multifilament yarn.

References Cited in the le of this patent UNITED STATES PATENTS 2,353,666 Hathorne et al July 18, 1944 2,755,616 Weller July 24, 1956 2,807,073 Stuewer Sept. 24, 1957 2,909,028 Comer et al. Oct. 20, 1959 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 125,848 Mar-ch 24,. 19641 Marjan Baebler hat error appears in the above numbered pat- Tt is heeby certified t that the said Letters Patent should read as ent requiring correction and corrected below.

Column 4, line I7, for "7 dem" read 7O dene column 5, line 4l, for "BOO t./m read SOOO iM/ma Signed and sealed this 4th day of August 1964,.,

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents ERNEST W. SWIDER Attesting Officer 

12. A FALSE TWISTED SUBSTANTIALLY UNIFORM PERMANENTLY CRIMPED CONTINUOUS FILAMENT STRETCHABLE SINGLE-END YARN OF SYNTHETIC RESINOUS TYPE HAVING AN ACTURAL UNIDIRECTIONALTORQUE AND A LATENT TORQUE WHICH DEVELOPS ON 